Presently known two-way envelopes capable of being made on high speed machinery and at costs which are substantially less than the commonly used enclosed return envelope generally comprise a front panel, a rear panel secured to the front panel to form a pocket, a sealing flap carried by one of the panels to enclose the pocket for the initial mailing and a return sealing flap carried by the other panel to enclose the pocket on its return trip.
If the return sealing flap is severed from its panel in the initial opening of the envelope by the recipient, the two way function is destroyed and the envelope will often be discarded. Severing of the return sealing flap usually occurs from the careless use of letter openers since automatic letter openers merely cut a thin portion from the top of the envelope.
In U.S. Pat. No. 2,317,335 issued Apr. 20, 1943 to Whitman, the return sealing flap is folded upon the rear panel to overlie the outer surface of said panel. The intial sealing flap is drawn over the return flap to cover and protect it during the initial mailing. While explicit instructions for opening the initial sealing flap are set forth in the patent, a letter opener inserted beneath the initial flap could also sever the return flap. U.S. Pat. No. 3,084,846 issued Apr. 9, 1963 to Clegg shows a similar structure in which there is provided a window in one of the panels. Here again, a letter opener blade slipped beneath the initial flap could accidentally engage the return flap and sever it.
U.S. Pat. No. 3,558,040 issued Jan. 26, 1971 to Krueger discloses a return sealing flap tucked into the envelope pocket during the first mailing. The said sealing flap is slipped out of the pocket and used to secure the envelope during the return mailing. Krueger recognizes the danger of accidental severing of the return sealing flap and teaches making the front panel larger than the rear panel to solve the problem. The Krueger envelope may, nevertheless, be subject to the shortcomings of other two-way envelopes upon opening, particularly when the insertions carried by the envelope buckle the return sealing flap within the pocket.
Automatic processing of mail often requires processing information to be carried upon the front of the envelope. Such information may be located close to the bottom edge of the envelope. The return sealing flap is then required to carry the processing information at the same location near the bottom of the envelope. Prior art two-way envelopes limit the length of the return sealing flap and do not lend themselves to automatic processing under the above conditions.
Accordingly, it is an object of the present invention to overcome shortcomings in prior art two-way envelopes.
Another object of the present invention is to provide a two-way envelope in which the return sealing flap is protected from damage during transit and upon opening.
A further object of the present invention is to provide a two-way envelope capable of being manufactured on high speed web-type machines and stuffed on inserting machines.
Still another object of the present invention is to provide a two-way envelope in which the return sealing flap covers substantially all of the front face of the envelope on the return trip.